The invention relates to a magnetic displaying device which is intended to be hung on a wall (hereinafter referred to as a "a wall-hanging type magnetic displaying device" when applicable) which includes a displaying panel having a magnetic panel enclosing a dispersed liquid containing magnetic particles, an erasing magnet slidably provided on the rear surface of the magnetic panel, and a displaying magnet for moving the magnetic particles in the dispersed liquid.
In such a magnetic displaying device, a liquid containing dispersed magnetic particles is enclosed between two substrates. Accordingly, when the magnetic force of the displaying magnet is applied to the magnetic particles through the substrate on the displaying side, only the magnetic particles affected by the magnetic force are moved as a result of which contrast occurs in the liquid providing a display on the panel. If the magnetic force of the erasing magnet is exerted on the magnetic perticles through the opposite substrate, the magnetic particles are moved towards the substrate as a result of which the display is erased.
In order to prevent sedimentation of the magnetic particles which have formed a display, a yield value is provided in the dispersed liquid. That is, the magnetic particles are maintained at the positions in the liquid where they have been moved by the magnetic force. Accordingly, the erasing magnet must have a magnetic force sufficient to overcome the yield value to move the magnetic particles in the liquid. If the erasing magnet passes over the magnetic particles before the movement of the magnetic particles has been completed the magnetic particles discontinue their movement. Accordingly, the magnetic displaying device is disadvantageous in that it is necessary to scan the displaying panel with the erasing magnet many times to complete erase the display.
This difficulty becomes especially troublesome when the magnetic panel is used on a wall as in that case it will typically be used as a general purpose magnetic panel by many persons and consequently the erasing magnet scanning speed is not always constant with the result that displays cannot be erased completely.
In addition, the wall-hanging type magnetic displaying device may installed at a position on the wall which is high above a person, for instance. In this case, it is difficult for a small person such as a child to satisfactorily operate the erasing magnet to erase the display. Thus, the operability of the device in erasing displays may be considered poor when such a conventional magnetic display device is installed at a high position.